CODEWITHSUNDEEP
mpimaster-slave
Alex
Alex

Reputation: 27

How to improve this programme to work master also

In this mpi programme only works slave nodes. How to modify it to work master also. Because working of the master also improve the performance of the system.

int A,B,C, slaveid,recvid,root, rank,size;

MPI_Init(&argc, &argv);

MPI_Comm_rank(MPI_COMM_WORLD, &rank);
MPI_Comm_size(MPI_COMM_WORLD, &size);

/*-------------------------- master ------------------------------*/

if(rank == 0){

    N =10;  

    for(slaveid=1; slaveid<size; slaveid++){

       MPI_Send(&N, 1, MPI_INT, slaveid, 1, MPI_COMM_WORLD);
    }

    for(recvid=1; recvid<size; recvid++){
        MPI_Recv(&A, 1, MPI_INT, recvid, 2, MPI_COMM_WORLD, &status);

    printf(" My id = %d and i send = %d\n",recvid,A);
    }
}

/*-------------------------- Slave ------------------------------*/

if(rank>0){

    MPI_Recv(&B, 1, MPI_INT, 0, 1, MPI_COMM_WORLD, &status);

    C = B*3;

    MPI_Send(&C, 1, MPI_INT, 0, 2, MPI_COMM_WORLD);

}

MPI_Finalize();

}

Upvotes: 0

Views: 101

Answers (1)

High Performance Mark
High Performance Mark

Reputation: 78324

Within the block delimited by 

if(rank == 0){

}

insert, at the appropriate location, the line

work_like_a_slave(argument1, argument2,...)

The appropriate location is probably between the loop that sends messages and the loop that receives messages so that the master isn't entirely idle while the slaves toil.

Whether this has a measurable impact on performance depends on a number of factors your question doesn't provide enough information on which to base a good guess; factors such as: how many slaves there are and therefore how busy the master is sending and receiving messages, how much work each process does compared with the messaging it does, etc.

Be prepared, if the numbers work against you, for any measurable impact to be negative, that is for pressing the master into service to actually slow down your computation.

Upvotes: 1

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